J. Anim. Breed. Genet. ISSN 0931-2668 EDITORIAL Marbled Japanese Black cattle Wagyu is a general term used for native Japanese beef introduce Western food habits and other aspects of breeds (‘wa’ means ‘Japanese’ and ‘gyu’ means ‘cat- Western culture. Various British and continental tle’). Wagyu cattle consist of four beef breeds, all of breeds such as Shorthorn, Brown Swiss, Devon, Sim- which belong to Bos taurus: the Japanese Black, Japa- mental and Ayrshire were imported into Japan and nese Brown, Japanese Shorthorn and Japanese were crossed with native cattle by local prefectural Polled. In 2010, a total of 737 281 breeding cows of governments. However, none of these crossing efforts all four Japanese beef breeds were counted nation- were successful, due to the inferior draft performance wide; the Japanese Black cattle is the predominant of the crossbreds, although crossbred animals were breed and accounted for 97% with nationwide distri- larger and produced more milk. No further crossing bution. The other three breeds are minor and regional with foreign breeds was conducted after 1910. Never- breeds; the Japanese Brown is mainly distributed in theless, because of the crossbreeding under local gov- Kumamoto Prefecture in Kyushu island and Kochi ernments, the genetic diversity of the breeds was Prefecture in Shikoku island, the Japanese Shorthorn greatly expanded. in Tohoku region (north-eastern areas in main island) In 1919, a registration system was organized in each and the Japanese Polled only in Yamaguchi Prefecture prefecture according to the decision of the Japanese (western area in main island). government, and selection on favourable traits utiliz- About 510 thousand heads of Japanese beef (Wag- ing variation from both native and foreign ancestors yu) feedlot steers and heifers and culled cows are was started with the aim to have uniform conforma- slaughtered annually, and beef supply from Japanese tion and quality of the cattle. Consequently, the cattle beef cattle was 155 thousand tons (17.8% of total beef raised in the prefectures formed the four breeds; the supply including imported beef) in 2010. The average Japanese Black, Japanese Brown and Japanese Polled retail prices in meat shops for outside-loin and sirloin were established as pure breeds in 1944, followed by cuts from Japanese beef cattle are $55 and $113/kg, the Japanese Shorthorn in 1957. Since the 1960s, respectively, whereas those from the USA beef are with the rapid growth of the Japanese economy and $21 and $40/kg for the same parts. the mechanization of crop production at the time, the Historically, over approximately 1200-year span use of the breeds has shifted from draft animals to beef from the year 676 until the Meiji Revolution in 1868, production. The official cattle performance and prog- there had been no meat consumption culture in Japan eny testing programmes for beef production started in because Buddhism prohibited eating meat. Japanese 1968, and the testing schemes in central stations were native cattle were used only as a draft tool for paddy established. rice cultivation, mining and transportation. During the In Japan, the carcass value has been determined by early 19th century, inbred strains based on dam lines meat quality, primarily the degree of marbling. Since were built up by breeders (wealthy farmers and cattle the liberalization of beef importations in 1991, mar- dealers) in mountain areas in Chugoku districts at the bling has been emphasized more and more as a reason west side of Japan’s main island, Honshu. These strains to differentiate domestic beef from imported beef. were named ‘Tsuru’, which means ‘vine plants’. Inter- Clear positive genetic trends for marbling of Japanese estingly, the breeding procedure used was similar to beef breeds have been realized by introducing field the close and continued inbreeding of Hereford and progeny testing programmes using carcass records col- Shorthorn cattle practiced by Robert Bakewell and the lected at slaughter houses and processed by the BLUP Collong brothers in England. It is notable that the method (Sasaki et al. 2006, J. Anim. Sci., 84, 317–323). same types of inbred strains of cattle were established Marbling is evaluated using the 12-point beef mar- during the same period in both the Western world and bling standard (BMS score 1–12) with number 12 the Far East although there was no academic or cul- being best. The Japanese Black is known to have tural exchange between the two worlds in those years. extremely superior marbled beef-producing ability After the Meiji Revolution, the new govern- among the four breeds. There is much genetic varia- ment discontinued the prohibition on eating meat to tion in the BMS score in the Japanese Black (Oyama © 2014 Blackwell Verlag GmbH • J. Anim. Breed. Genet. 131 (2014) 1–2 doi:10.1111/jbg.12073 Editorial 2012, Anim. Sci. J., 82, 367–373), and it is noticeable It is hypothesized that, as the adipose tissue is one that there is a low or even negative genetic correlation of the primary storage sites of vitamin A (Tsutsumi between the BMS score and the subcutaneous fat et al. 1992. J. Biol. Chem., 267, 1805–1810), Japanese thickness for Japanese Black (Oyama 2012) and also cattle may have genetic potential by itself to increase Japanese Brown (Hirooka et al. 1996, J. Anim. Sci., 74, the fat content in muscle (marbling) for storing vita- 2112–2116). These favoured characteristics of the min A when the dietary vitamin A level is low. Japa- breeds encourage the breeders who want to produce nese native cattle have usually been kept in barns highly marbled beef without increasing external fat. over the winters in mountain and hilly areas, because Why do only Japanese beef breeds (in particular, green forage (with an abundance of vitamin A) is not the Japanese Black) have the ability to produce extre- available in the winter due to withering and the mely highly marbled beef? It is said that most native heavy snow cover. This poor environment may have breeds are products of the natural environment and made Japanese native cattle tolerant against vitamin the humans who raise them. Japan is located at the A shortages, and it might have enhanced their genetic north-eastern edge of the Asian monsoon climate potential to increase intramuscular fat deposits (mar- belt, and the climate is thus temperate and humid, bling) by natural and artificial selection over the long which is quite suitable for rice production. However, term. there are limited grazing and pasture areas in Japan In the USA, marbling has long been used as a factor because of the very marked changes of the four sea- in the USDA beef quality grading system as a visual sons (hot and humid summer and cold winter), espe- indicator of quality. In fact, some US consumers con- cially in remote sites in the mountain and hilly areas, sider marbling indicative of quality and palatability, where Japanese native cattle (especially the ancestors whereas others prefer lean beef in light of health pref- of the Japanese Black) have been raised for draft use. erence. Marbling is also related to tenderness, which Kato et al.(J. Anim. Sci., 2011, 89, 951–958) reported is one of the most important factors influencing the that a highly negative genetic correlation between the acceptability of beef. Again, Japanese beef breeds serum vitamin A concentration and the BMS score (Wagyu) raised in Japan are very pure breeds; foreign was obtained in the final stage in the feedlot period genes have not been introduced into the breeds for for crossbreds (so-called ‘F1’ breed in Japan) of over a century. The Japanese breeds could well Japanese Black sires and Holstein dams raised under become international breeds in the near future due to vitamin A restriction in the finishing diet, which is their unique characteristics. widely practiced in feedlot situations in Japan. This result was the first report for a negative genetic H. Hirooka correlation between the serum vitamin A concentra- Graduate School of Agriculture, tion and the degree of marbling, although it is well Kyoto University, known that restriction of dietary vitamin A produces Kyoto, Japan higher marbling scores for Japanese Black cattle (Oka E-mail: [email protected] et al. 1998. Meat Sci., 48, 159–167). 2 © 2014 Blackwell Verlag GmbH • J. Anim. Breed. Genet. 131 (2014) 1–2.